Effects of roads on wildlife in an intensively modified landscape

Abstract

This paper examines the ecological impacts arising from road networks and the potential ameliorating effects of roadside habitat in a highly modified landscape. A UK focus has been adopted to illustrate the effects of roads in a landscape with a long history of land use and intensive land management where the impacts and the potential for improvement are considerable.The impacts of roads in the ecological landscape include habitat loss, fragmentation, and degradation. These interrupt and modify natural processes altering community structures and in the longer term, population dynamics. The large number of fauna fatalities each year from road traffic accidents is also of concern. Road verges can however also provide habitat opportunities and restore connectivity in an otherwise fragmented landscape offering potential to offset some of the adverse impacts of the existing road network. This review demonstrates that roads can present both ecological costs and ecological benefits although currently there is insufficient evidence to confirm some of the key theories which relate to the impact of the barrier effects (at population level) or the value of road verges as ecological corridors. In the absence of complete information the full extent of the problems and opportunities cannot be gauged and every effort should be made therefore to enhance the habitat adjacent to existing roads and to constrain further fragmentation caused by the development of the existing road network. Where further construction is unavoidable conditions should be enforced to prevent roads from reducing further the remaining habitats of conservation value and the connectivity between such habitats.

Effects of Roads on Animal Abundance: an Empirical Review and Synthesis

“…In conclusion, our review of the empirical literature revealed many more population-level studies on road effects than we were initially expecting based on statements in the literature (Underhill andAngold 2000, Roedenbeck et al 2007). Studies have been conducted on a wide range of taxa, and overall there is strong evidence for negative effects of roads at the population level.…”

“…In support of this claim, Roedenbeck et al (2007) cite review papers published in 2000 and earlier. In one of these review papers, Underhill and Angold (2000) state that " [h] ard information is still lacking for the effect of roads and traffic at the population level," and in support of this statement they cite a review paper published in 1991. So, the claim that there are only a few road ecology studies at the population level (Roedenbeck et al 2007) is based on reviews and assertions that are now 8-17 years old.…”

Bird Casualties on European Roads — A Review

“…In the majority of cases, the authors did not measured traffic density, despite the fact that this could be a major factor affecting the probability of collision (Underhill & Angold 2000). Measurements of the mean speed of vehicles were also lacking.…”

“…Reviews of the impact of road systems and traffic on the landscape, surrounding environment and wildlife have thus far been published by Bennett (1991), Forman (1995), Forman & Alexander (1998), Trombulak & Frissell (2000), Underhill & Angold (2000) and Seiler (2001). The environmental impact of road traffic is greater than usually suspected.…”

Minor rural road networks: values, challenges, and opportunities for biodiversity conservation

“…As a result, most attention by environmental researchers has focussed on the negative effects of highways in relation to wildlife (e.g. Trombulak and Frissell 2000, Forman et al 2003, Underhill and Angold 2000, and methods to mitigate the conflict between transportation and nature (Morelle et al 2013).…”